First a word of caution. You may need to consider the possibility that I may be conflicted. I am a graduate (1970) geologist who spent over half a century working in the mining and mineral resources sector. More damning yet: for much of that time, I worked in coal.
Is a geologist a scientist?
Sheldon Cooper (of TV’s The Big Bang Theory) has a dim view of the discipline, believing that “Geologists are the Kardashians of Science”.
A geology student colleague once described a geologist as “part navvy, part scientist”. The term navvy derives from navigator, a labourer working on the construction of canals or navigations. This description is apt. William Smith, sometimes known as the father of geology, was an engineer involved in the construction of the UK’s canal infrastructure. He made early geological observations and, in 1815, published the first detailed national geological map of the UK, or of any country. Copies of “The Map that Changed the World” are on display at Burlington House in London and at the Sedgwick Museum of Earth Sciences, Cambridge University. Outlines of the Lancashire and Cumbria coalfields are recognisable on Smith’s 200-year-old map.
A geologist is not a traditional white-coated, laboratory-based scientist then, but a grubbier-handed, perhaps more down-to-earth version? But a seeker of truth nonetheless. (He doubts; therefore he thinks; therefore he is, to paraphrase an oft-misquoted phrase). Geology tells us that Rupert Lowe is correct when he says climate has always changed. He forgets to mention that there have also been 5 mass extinctions, many of which have been linked to climate change, though (in these instances) climate change was not driven by humans.
Indeed, the climate was changing – the world was emerging from the last glaciation, and warming long after the start of the Industrial Revolution. What is considered different about recent change is its rapid pace.
Greenhouse gases (GHGs) and pollutants
Carbon Dioxide, CO2: caused by Energy and heating, mostly through coal-fired electricity generating plants, is estimated to account for around 34% of CO2 anthropogenic emissions, and transportation adds a further 14%.
Sulphur Dioxide, SO2: Coal combustion in power plants is the single largest anthropogenic source of SO2 globally, accounting for approximately 45–50% of human-caused emissions. Transportation is another important contributor, mainly through maritime shipping. (Note: road transport fuels have been heavily regulated for sulphur content since 1996 in the UK).
Limits on the sulphur (S) and ash content of coal (important contributors to SO2 and particulate pollution) for various applications are often set by market specifications and are typically less than 1% S and 10% ash.
Methane, CH4: an important greenhouse gas (GHG) has properties which differ from CO2 in several respects: it is present in much lower proportions in the atmosphere, where it has a much shorter lifespan, and it has a much greater Global Warming Potential (GWP). Methane can also be released during coal mining. I regret to say that this is an area where the industry may not always have been fully open and transparent.
Clean up activities (with unwelcome consequences)
Acid rain was a serious environmental problem mainly caused by emissions of sulphur dioxide (SO2) from coal-fired power stations. Emissions peaked in the UK in 1970; over the next 50 years, they were reduced by over 90%. The reduction was achieved by fitting flue gas desulphurisation equipment (scrubbers) to UK coal-fired power stations and by using less coal. Similar legislation and action followed in the USA and Europe. China, currently the world’s largest coal producer, is implementing an ongoing SO2 reduction programme. Ironically, although UK coal mines were closed, and despite the ‘dash for gas’ (methane, has been described as the “least grubby of the fossil fuels”) most Natural Gas is now imported. The UK’s reliance on imported coal increased steadily from the 1990s until 2011, since when there has been a decline in the use of coal for power generation in the UK.
In parallel, International Maritime Organisation (IMO) shipping introduced new low-sulphur fuel restrictions in 2020.
Back in 1975, the UK coal industry was keenly aware of two environmental concerns, both related to aerosols emitted during the combustion of coal in power stations – Acid Rain and Climate Change (at that time there was no certainty whether the climate was cooling or warming).
An aerosol is a suspension of fine solid or liquid particles in a gas. In the case of emissions from a coal-fired power plant, the main concerns for acid rain are sulphate and nitrate aerosols, particularly SO2, which can form dilute sulphuric or nitric acid upon reaction with rainwater. Sulphur Dioxide is a pollutant associated with respiratory illness and deaths in the population. Its removal from the atmosphere was welcome; less welcome was the effect the changes had on climate by removing its cooling effect and adding warming. In an opinion piece published in Scientific American, an author put forward the idea that international agreements on “SO2 and “acid rain” are an example of what can be achieved.
Meanwhile binding, meaningful international agreements on climate change are proving more elusive.
There are two main ways in which aerosols can influence climate:
- By affecting the amount of solar radiation that reaches the earth through the atmosphere, thereby changing the earth’s radiative balance.
- By affecting the way clouds form, as clouds themselves have climate influence.
NASA considers that most aerosols, including SO2, are cooling – that is, they reflect a proportion of the sun’s incoming energy back into space. The result of the process is described as atmospheric brightening and the increased energy reaching the Earth’s surface can be estimated in terms of watts per square metre (w/m2).
It is estimated that since the Industrial Revolution the finest aerosols in the atmosphere have increased by 60%. The net effect may have reduced the warming effect by about 50%. Without aerosols, NASA models suggest that the Earth would be 1°C hotter.
Cleaning up sulphur pollution, which is beneficial for human health, may remove some of the atmospheric cooling that had previously masked a proportion of greenhouse warming.
The substitution of natural gas for coal in electricity generation, referred to as the “Dash for gas” in the UK, was game-changing for the coal industry and contributed significantly to SO2 reduction. While natural gas combustion in a power plant produces roughly 50% less CO2 than coal, methane leakage throughout the supply chain significantly reduces this advantage. Analysis from the Clean Air Task Force notes that accounting for these leaks and using methane’s shorter lifetime and higher 20-year global warming potential can substantially reduce the advantage of natural gas.
Renewables: Solar and wind, produce zero CO2 per kWh during their operating phase, and even after a full life-cycle assessment, including infrastructure construction, they produce a fraction of the emissions of fossil-fuel generators.
Does coal get a bad press?
A constant companion since 1970 was a booklet, “A Glossary of Terms for Coal and Coke”. The term dirty coal does not appear among the 870 terms defined, although dirt does, we may have used ‘dirty coal’ informally to describe coal varieties with higher levels of ash, sulphur, or other pollutants. For example, dirty coals contributed to London’s Great Smog of 1952, caused by a combination of weather and pollution. Replacing them with cleaner coals and smokeless fuels under the Clean Air Act of 1956 provided part of the solution. The Act was updated in 1996, and some coals, anthracites, and smokeless fuels are still permitted for domestic heating. More recently, London’s Ultra Low Emissions Zone (ULEZ) has made the city’s air even cleaner.
So, dirty coal is not a new phrase, but its use may have changed. What was once an industrial technical term has become a media environmental and climate pejorative.
It is more difficult to determine when the change was widely adopted and whether the language followed policy change or helped drive it. Was the language/policy based on consideration of how to conduct an orderly, calm, climate- and socially sympathetic transition away from coal, or was it simply a question of dirty coal has to go?
This geologist, fairly immersed in the industry and initially sceptical of climate change, has come to accept that the weight of evidence supports the conclusion that the Earth is warming. Perhaps his scientific instincts have prevailed?
I believe the rapid acceleration occurred much later than the Industrial Revolution, perhaps in the 1980s. Using the former as a reference point, with countries setting their own reference-year targets and expressing temperature change as a plus-or-minus figure relative to the reference year, is unhelpful and misleading; expressing temperature in absolute terms would be more scientific and transparent.
Nor do I like the term Net Zero. The qualifying adjective offers some wiggle room and comfort in the as-yet unproven idea that CO2 can be substantially offset or removed by natural or engineered means.
A recent post on Linkedin by someone working in the field of Carbon Capture Use and Storage (CCUS) in the North Sea estimated that, over 30 years of developing the technology, the total CO2 captured amounts to about three days of the world’s annual emissions.
The primary focus should be on reducing GHG emissions. Methane’s short atmospheric lifetime intriguingly suggests that reducing methane emissions could rapidly reduce the total GHG load.
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